U.S. Pat. No. Re: 28,921 discloses an automatic visual sensitivity and blind spot measuring apparatus for projecting a spot at different locations on a screen to be viewed by the person being tested along with means for the person to indicate perception of the spot for subsequent evaluation.
U.S. Pat. No. 1,990,107 relates to a reflectoscope used in the examination of an eye. The reflectoscope includes mirrors for reflecting an image so that the eye can be observed in the correct orientation to prescribe lenses for correcting refractive dysfunctions.
U.S. Pat. No. 4,264,152 relates to an apparatus for moving an image of a target in certain preselected ways to stimulate predetermined types of eye movements.
U.S. Pat. No. 4,298,253 relates to an apparatus for presenting test images to a viewer at different distances without modifying the visual angle or acuity of the images.
U.S. Pat. No. 3,423,151 relates to auxiliary prismatic lenses mountable on an eye glass frame for use by persons having cataracts. The lenses extend the field of view of the person beyond that provided by ordinary lenses by focusing images beyond the range of the normal lenses onto the pupil of the eye.
U.S. Pat. No. 2,442,849 relates to a method for producing a pair of lenses for providing balanced binocular vision.
U.S. Pat. No. 4,772,113 relates to eyeglasses for improving the vision of people with macular degeneration, optic nerve damage or similar low vision problems, in which their central vision has deteriorated. The eye glasses include two lens assemblies, each having a magnifying lens with two convex surfaces and a reducing lens with two concave surfaces. The reducing lens incorporates a prism ring which shifts and focuses a highly intensified light image onto an undamaged peripheral portion of the retina. A disadvantage of these eye glasses is that the highly magnified and intensified light image would be focused on the bad or damaged peripheral portion of the retina. Another disadvantage of these glasses is that the lens do not have a central clear or non prism area for accommodating the person's good central vision. Also, in those instances where the highly magnified and intensified light image would strike the central functional area of the retina damage and/or overlapping would occur, resulting in a blind area or diplopia (double vision).
U.S. Pat. No. 4,673,263 relates to eyeglasses for enhancing the vision of people with macular degeneration, optic nerve damage, or similar low vision problems in which their central vision has deteriorated. The eyeglasses comprise of a single element prismatic lens with bifocal which unlike U.S. Pat. No. 4,772,113 which projects a strong magnified beam of light to the macula.
U.S. Pat. No. 5,155,508 relates to eyeglasses for enhancing the vision of people that have retinitis pigmentosa or glaucoma with constricted fields. The eyeglasses include three functional prisms and a non prism area spaced about a central portion. Two of the three prisms are oriented base out on the horizontal axis, the third prism is located on the lower vertical axis, base out, the non prism area is opposed to the third prism across the central portion.
U.S. Pat. No. 3,628,854 relates to a fresnel prism for special applications, such as diagnostic testing. The fresnel prisms are mounted to normal prescription corrected glasses by capillary action The capillary mounting is subject to air bubbling during temperature and humidity changes. The fresnel prisms have relatively poor light transmission and the multiple images transmitted or projected to the eye are blurred due to the many concentric prismlets that are pressed into the soft plastic. The fresnel prisms have a number of other disadvantages such as: projection of people in crowds when people move in all directions, this causes diplopia especially when the right eye looks to the right and the left eye is looking through the nasal edge of the left spectacle lens, this is also true when the eyes are looking to the left.
These multiple prismlets reduce light transmission, which reduces vision and causes night blindness and mobility problems. The multiple concentric prismlets cause many reflections of the same object, especially light bulbs, and hence, "one thousand points of light", which causes chromatic dispersion. Due to the number of multiple concentric prismlets, contrast is greatly reduced and patients are constantly looking through a fine grid. With fresnel prisms the patient must rotate their eye to look into the prism to see the expanded field.
U.S. Pat. Nos. 4,779,977 and 4,288,149 and The Optician, Volume 163, No. 4237, page 18, dated 1972 all relate to the concept of mounting or cementing small prismatic buttons or prisms to a patient's normal prescription corrected glasses. An exemplary reference of such small prisms are disclosed by Dr. Norman Weiss in the referenced The Optician. The primary disadvantages or difficulties associated with the use of such buttons and/or prisms is prism blur which is difficult to tolerate, creating confusion between frontal and peripheral images particularly in crowds where people are moving in all directions causing diplopia for the wearer.
An eye disease known as neovascular senile macular degeneration (N.S.M.D.) in which the central vision, (macula) is greatly impaired, often results in blindness by virtue of blood vessels growing and bursting in the macula of the eye.
A known eye glass modification intended to expand the central field of view for people having retinitis pigmentosa, glaucoma, hemianopia involves the amorphic telescope lens system, in which one or more telescopes are mounted on each eye glass. These telescopes minify the images so that more information can be seen at one time in the same field. Disadvantages of this form of field expansion is that multiple images are seen by each eye with the images approximately half size so that detail is lost. Also, the telescope(s) extend outwardly a significant distance from the eye glasses and are cosmetically very unappealing. These eye glasses with telescopes mounted are several times heavier than normal glasses making them uncomfortable to wear and constantly slipping from the wearer's ears and nose due to the generated torque.
Another known vision expanding lens in the prior art, involves the use of a see-through reflector or mirror, functioning as a beam splinter, mounted on the eye glass frame extending from the nose at a predetermined angle. The disadvantages of this type of vision expanding lens are that the eye glass wearer sees two separate images, front and rear which can be quite confusing. The mounting of the reflector or mirror to the eye glass frame is complicated, and results in the reflector or mirror mounted in an exposed position where it can be readily damaged and/or disoriented from the predetermined position.
Still another attempt to expand the field of persons with poor vision involves special high-powered magnifying glasses capable of magnifying an object up to six times, while allowing vision from the peripheral area to enter the eye. Disadvantages of this approach are that these glasses resemble goggles and protrude nearly three inches from the eye and nose. They must be worn with soft contact lenses, they are heavy and cumbersome, and cosmetically unappealing.
Therefore, a need exists for an image enhancing lens having a greater transmission of available light by reducing at least one of reflection, refraction and absorption of light by the lens. The need also exists for lenses for eyeglasses to enhance the field of view of persons suffering from retinitis pigmentosa, glaucoma with constricted fields, hemianopia, macular degeneration, myopia, nystagmus without the person suffering the problems and disadvantages of the prior known efforts to expand a person's field of view. A further need exists for inexpensive, light weight, single element prescription corrected eyeglasses with bifocal(s) that are cosmetically appealing. The need also exists for an image enhancing lens that can be readily employed in a variety of optical systems, wherein the energy transmission through the lens is enhanced without introducing significant aberrations.